Sakurai: But, you know I get requests like, “Please put Goku in”
Sugita: GOKU!?
Sakurai: “Please put Spongebob”
Sugita: SPONGEBOB?!
Sakurai: That’s impossible.
Sugita: Spongebob’s games are only sold abroad!
Sakurai: That’s right
Sugita: The really energetic, yellow square right?
Sakurai: Yes.
Sugita: Even Spongebob…
Sakurai: Well, those kinds of requests are pretty common.
Sugita: What about Yukawasen*, or Segata Sanshiro?
Sakurai: (laughs)
Sugita: …well I’m glad Sonic’s in.
Sakurai: That’s the point of Mii Fighters
https://sourcegaming.info/2015/03/22/mewtwo-dlc-takamaru-and-sakurais-nico-nico-appearance/